Roche has reported that Evrysdi (risdiplam) met the primary goal of the FIREFISH Part 2 study in infants aged one to seven months with symptomatic Type 1 spinal muscular atrophy (SMA).

A survival motor neuron 2 (SMN2) splicing modifier, Evrysdi can potentially treat SMA developing due to mutations in chromosome 5q that cause deficiency of SMN protein.

FIREFISH is an open-label, two-part clinical trial in paediatric Type 1 SMA patients.

The first dose-escalation part of FIREFISH enrolled 21 infants. It evaluated the safety profile of Evrysdi and identified the Part 2 dose as the primary goal.

The pivotal, single-arm Part 2 of the trial involved 41 infants with Type 1 SMA who were treated for two years. This part is followed by an open-label extension study.

The primary goal of Part 2 was to evaluate the efficacy, determined by the proportion of subjects sitting without support after 12-month treatment.

Data from the Part 2 study showed that 29% of infants could sit without support for a minimum of five seconds by 12 months, thereby meeting the primary goal.

Furthermore, 93% of subjects were alive while 85% did not require continuous ventilation at month 12.

Nearly 56% of infants had Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) score above 40% and 90% showed a rise in the score by at least four points on receiving Evrysdi.

The trial also met a secondary goal with 78% of subjects categorised as Hammersmith Infant Neurological Examination 2 (HINE-2) responders, which assessed motor function through the ability to control head, sit, voluntarily grasp, kick, roll, crawl, stand and walk.

Furthermore, the safety of Evrysdi in the trial was in line with its already reported profile.

Infection in the upper respiratory tract, pneumonia, pyrexia and constipation were some of the most common adverse events (AEs) reported in the Part 2 study.

This Part 2 data has been published in the New England Journal of Medicine.

Roche chief medical officer and Global Product Development head Levi Garraway said: “These results have been further confirmed in the recently presented 24-month data showing Evrysdi continued to improve motor function, doubling the number of babies able to sit without support from month 12.”

As part of a partnership with the SMA Foundation and PTC Therapeutics, Roche is carrying out Evrysdi’s clinical development.

In April, PTC Therapeutics reported 24-month data from Part 2 of the FIREFISH trial, which demonstrated that infants with type 1 SMA continued to show improvements in survival and key motor milestones after two years of treatment.